#$&*
Phy 232
Your 'measuring atmospheric pressure' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
** your comment **
** How does the system behave and how does it 'feel'? **
When I squeeze the bottle, the water in the pressure tube causes the air column to decrease in size. The more I squeeze the bottle, the more that the tube is effected (the shorter the air column becomes). At a certain point, I can no longer really squeeze the bottle.
** Length of the air column in units of your measuring device: **
I chose to use the scale reduction found on the third page in the packet in this experiment, as I believe I will be able to (with relatively accurate precision) determine the measurements in this lab to this extent. I considered using a smaller reduction, but ultimately decided it would not deliver precise nor consistent results, as it would be difficult to read such small measurements.
** Your report of the vertical position of the first mark relative to the water surface of the first mark, the length of the air column in units of your selected measuring device, and the two meniscus positions observed with each of your five trials. **
52
I used my measuring device by lining it up against the bottle, starting at the table top and going upward. My scale required two taped portions. My maniscus was lined up with 12.5 while my stopped read 22.5. Becuase the first strip only went to 42, we can take and add 42 to 22.5 and then subtract the initial height of the maniscus, giving us 52.
** Your report of the vertical position of the second mark relative to the water surface of the first mark, the length of the air column in units of your selected measuring device, and the two meniscus positions observed with each of your five trials. **
12.5, 17.9
12.5, 18.0
12.5, 17.9
12.5, 17.8
12.5, 18.0
As pressure was applied to the bottle, the meniscus raised vertically. The data taken seems to be consistent, and the scale chosen seems to be fitting for the experiment. I obtained the measurements by taking the top mark at the maniscus and indicating the relative change. Based on the information gathered, it is clear that these 5 trials proved to be precise (consistent).
** Your report of the vertical position of the highest mark relative to the water surface of the first mark, the length of the air column in units of your selected measuring device, and the two meniscus positions observed with each of your five trials. **
22.4
18.2 cm
12.5, 21.9
12.5, 21.6
12.5, 22.1
12.5, 22.0
12.5, 22.0
Again, as pressure was applied, the meniscus raised vertically. However, it seems that this applied pressure had less of an effect than it did for the first mark. Also, the data collected, while still reasonably accurate, is definitely not as consistent as before, as it was more difficult to accurately squeeze to the second mark.
** Your report of the vertical position of the 'in-between' mark relative to the water surface of the first mark, the length of the air column in units of your selected measuring device, and the two meniscus positions observed with each of your five trials. **
36.0
18.2 cm
12.5, 26.8
12.5, 26.8
12.5, 27.1
12.5, 27.3
12.5, 12.7
As before, as the bottle is squeezed the maniscus rises. Again, the amount increased is a lower amount but this can be partially attributed to not reaching the third mark. However, if you assume that increase in rate were to continue up to the third mark, this would still remain true.
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45 min
The meniscus positions shouldn't be changing the several centimeters, with only 10-12 cm changes in vertical level of the water. I'm not sure you've reported your data correctly.
The main question is how long the air column was with each vertical position. Can you give me a list of air column lengths, just to be sure you have good data for the next experiment?